Nock



FIG. 1 is a top perspective view of a nock incorporating my new design;

FIG. 2 is a bottom perspective view of a thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear end view thereof;

FIG. 6 is a front end view thereof;

FIG. 7 is a left side view thereof, to which a right side view is a mirror image; and,

FIG. 8 is a left side cutaway view thereof.

The broken lines in the drawings illustrate portions of the nock that form no part of the claimed design. 

CLAIM The ornamental design for a nock, as shown and described. 